Alton, who lives in Manhattan, is listed on the New York State Sex Offender Registry.

In the letter, Headmaster Nathaniel Conrad and Jeffrey Edwards, chairman of Pingry's board, say the school has hired T&M Protection Resources to conduct a "thorough, independent investigation into the events of the 1970s."

Pingry has also notified law enforcement authorities of the allegations.

The school is asking anyone with information or if they were personally harmed by Alton to contact Conrad at 908-647-5555. ext. 1232, or email him at nconrad@pingry.org. They can also contact Laura Kirschstein of T&M Protection Resources at 212-916-8852 or lkirschstein@tmprotection.com.

Once the investigation is complete, Pingry will release the results, according to the letter.

"We want to assure you that we are taking this matter very seriously," Conrad and Edwards wrote. "While these events took place many years ago, we realize that they continue to cause pain for members of our community. It is sickening that an educator, entrusted with the responsibility of protecting children, would cause such suffering. Behavior of this nature is appalling and deplorable."

Conrad and Edwards wrote "we are both deeply pained by and sorry for the harm caused by Mr. Alton, and we wish to be as helpful to and supportive of his victims as we can be."